Photoaffinity labeling and biochemical characterization of binding proteins for pheromones, juvenile hormones, and peptides

Abstract

Radiolabeled photoaffinity analogs can be used to purify and characterize proteins involved in pheromone perception, juvenile hormone (JH) action, and neuropeptide reception. Several photoaffinity analogs and purification strategies are described for each of these physiological targets. First, a diazoacetate photoaffinity label is used to selectively modify the pheromone binding protein of the gypsy moth, Lymantria dispar. Reverse-phase HPLC is then employed to fractionate the male antennal proteins. Second, a tandem procedure involving preparative isoelectric focusing (IEF) and ion-exchange (IEX) HPLC is employed for the purification of the Manduca sexta hemolymph juvenile hormone binding protein (JHBP), which has now been cloned and sequenced. A separate application of this strategy for the purification of the 29 kDa JH I/methoprene receptor proteins from epidermal nuclei of M. sexta larvae is outlined. A new photolabel, farnesyl diazoketone, has been employed for the characterization of crustacean hemolymph methyl farnesoate binding proteins. Third, the development of neuropeptide photoaffinity labels is described for two systems: (1) the red pigment concentrating hormone (RPCH) of shrimp and (2) the allatostatins isolated from the brain of the cockroach Diploptera punctata.